1. Field of the Invention
This invention relates to equipment for applying double-ended flexible plastic labels to round containers, such as bottles and cans, on a high-speed production basis and without the use of a hot-melt, solvent or other separate adhesive, the labels being cut from a preprinted web of indefinite length of such labels by the labeling equipment itself.
2. Description of the Prior Art
U.S. Pat. No. 4,323,416 (Malthouse, et al) discloses equipment for applying double-ended labels from a web or strip of such labels to bottles in which there is provided an adhesive applicator to apply an adhesive substance to the label, after the label has been severed from the web or strip and before the label is applied to the bottle, to ennsure adhesion of the label to the bottle. Adhesive usually used in bottle labeling of this type is a hot-melt adhesive, and the use of such a hot-melt adhesive is messy and can be expensive because of the cost of the adhesive and the cost of equipment for storing it, handling it, and applying it. U.S. Pat. No. 4,406,721 (Hoffman) also discloses a system for applying double-ended labels from a web of a heat-shrinkable material of such labels to bottles or other containers, the system of Hoffman utilizing heat to cause the labels to shrink after they have been applied to the bottles. U.S. Pat. No. 3,235,433 (Cvacho et al.) describes a similar system in which a heat-activatable adhesive is heat-activated before the label is applied to the container.
U.S. Pat. No. 4,574,020, in the name of Harold R. Fosnaught, which application is assigned to the assignee of this application, and the disclosure of which is hereby incorporated by reference herein, now U.S. Pat. No. 4,574,020, recognized the objection to the use of a hot-melt adhesive in a container labeling system, especially in regard to a container labeling system that utilizes labels formed from thermoplastic materials. The invention described in the aforesaid U.S. patent application Ser. No. 555,758 eliminated the need for an applicator to apply a hot-melt adhesive to the label being applied to the bottle by utilizing an applicator to apply a solvent for the thermoplastic material in the label, such as methylene chloride as a solvent for labels formed from polystyrene, thereby eliminating some of the disadvantages inherent in utilizing a hot-melt adhesive in a bottle labeling system. However, strict environmental and occupational and health standards apply to the handling and use of solvents such as methylene chloride, and strict precautions must be followed in using such solvents in a label applicating system to comply with applicable regulatory standards. To ensure compliance with such standards, therefore, it is necessary to make expensive investments in applicating equipment and in the operation thereof.
U.S. Pat. No. 4,097,325 (Schnier) discloses a label applicating machine in which pre-cut plastic labels are transferred, in sequence, from a supply thereof in a magazine in a container labeling station, the transfer mechanism having heated, label contacting fingers to heat each label to a self-adhesive state to permit its application to a container without the need for a separate adhesive. However, this reference does not disclose the heating of plastic labels being severed from a web of such labels by the labeling equipment itself, and it does not disclose the structure for accomplishing this result.